Unusual sharp pan all over the area above my kneecap whenever I try to tighten it

Everytime I tighten or squeeze my kneecap the area around it mostly the area just above it starts hurting.. but as soon as I loosen it again , it stops hurting.... To explain the exact time it hurts is when I have an orgasm while lying on my back which as Probably all of you know tightens you kneecap ...it starts hurting.